1. Field of the Invention
The present invention relates to an ophthalmic apparatus, ophthalmic apparatus control method, and storage medium.
2. Description of the Related Art
Nowadays, various kinds of ophthalmic apparatuses using optical apparatuses have been used. For example, as an optical apparatus for observing an eye, a variety of apparatuses are used, including an anterior ocular segment imaging apparatus, fundus camera, and SLO (Scanning Laser Ophthalmoscope). Of these apparatuses, an optical tomographic imaging apparatus based on OCT (Optical Coherence Tomography) using multi-wavelength light wave interference is an apparatus (to be referred to as an OCT apparatus hereinafter) capable of obtaining a tomogram of a sample at high resolution. The OCT apparatus is becoming indispensable in outpatient clinics specialized in retinas as an ophthalmic apparatus. The OCT apparatus divides measurement light serving as low-coherent light into reference light and measurement light. The OCT apparatus irradiates an object to be examined with the measurement light, and makes return light from the object interfere with the reference light, thereby obtaining a tomogram of the object. In addition, the OCT apparatus can obtain a high-resolution tomogram by scanning a sample with measurement light. The OCT apparatus can therefore obtain a tomogram of a retina on the fundus of an eye to be examined, and has been widely used for ophthalmic diagnosis and the like for the retina. However, when the object to be examined is a living body such as an eye, distortion of an image caused by the movement of the eye becomes problematic. It is needed to measure the eye quickly at high sensitivity without the influence of movement of the eye.
Japanese Patent Laid-Open No. 2011-206519 or No. 2011-50430 discloses the following ophthalmic apparatus. The ophthalmic apparatus extracts the feature point of a fundus image from the first fundus image captured by fundus imaging for obtaining a fundus image. The ophthalmic apparatus further detects a feature point from the second fundus image different from the first fundus image. Based on the coordinates of the respective feature points on the fundus images, the ophthalmic apparatus measures a positional change of the fundus of the eye to be examined.
Japanese Patent Laid-Open No. 2003-546 discloses an ophthalmic apparatus which can display fixation target patterns different in size with a plurality of types of shapes, and stores a fixation target pattern for each eye to be examined.
However, the ophthalmic apparatus disclosed in Japanese Patent Laid-Open No. 2011-206519 or No. 2011-50430 uses a single fixation target. Since the vision is different for each object, the vision fixation of an eye to be examined becomes unstable, and no appropriate fundus image can be obtained.
The ophthalmic apparatus disclosed in Japanese Patent Laid-Open No. 2003-546 can switch and display fixation target patterns different in size with a plurality of types of shapes. However, the user manually switches the fixation target patterns. Changing the fixation target is cumbersome and does not consider the vision fixation state of an eye to be examined. Therefore, time is taken to select a fixation lamp suited to an object, placing a burden on the object.